The present invention relates to semiconductor image sensor devices which convert light into electric signals.
A cross-sectional view of a conventional semiconductor image sensor device is shown in FIGS. 15 and 16.
Electrodes for taking out the output of photo-transistors and circuits for driving the photo-transistors and reading out output thereof are provided on the same surface as that on which the arrayed photo-transistors is provided, and an electrode used for connecting an external circuit is provided on a illuminated surface side.
The above described structure of the conventional image sensor has the following drawbacks. Since the electrode and the wire used in wire bonding method and the like for connecting a circuit of a readout substrate to an external circuit passes above the illuminated surface side of the photo-transistor, a distance between the photo transistor and light source cannot be shortened less than a certain degree when the image sensor is mounted on the readout substrate. Further, in case the driving or readout circuits are built in the image sensor device the circuits are subjected to the influence of light. Moreover, since the electrode or the circuits for taking out the output is provided on the same substrate, aperture ratio of pixels cannot be increased.